California Avocado Society 1997 Yearbook 81: 33-43
THE NEW ZEALAND/AUSTRALIAN AVOCADO CONFERENCE—1997
BEFORE—DURING—AND AFTER ...
H. Leonard Francis
In 1992, as Production Research Coordinator for the California Avocado Society, I
visited Australia and New Zealand as part of the California Avocado Society's
international liaison program. A similar experience occurred in 1997. The New Zealand
and Australian avocado growers were holding a joint conference in Rotarua, New
Zealand, where I would be able to hear and meet with many avocado researchers of the
southern hemisphere. Part of my responsibility would be to use wisely time available
before and after the conference.
There was a lot that I had not yet seen in Australia, and I could take advantage of a
great opportunity to see before the conference the northeast region of Australia's
avocado industry, commonly called the Atherton Tablelands. It was my good fortune to
have Don and Del Lavers invite me to stay with them at their home and avocado grove
in Walkamin. They have quite a history, some of which I'll share later. My first activity in
Australia was to attend an awards program where Don Lavers was one of the award
recipients for his leadership in an avocado market development program.
The Atherton Tablelands is 30-40 miles inland from the coastline of Cairns and the
Great Barrier Reef. There is a mountain range that separates it from the coast. The
climate is tropical. There are close to 2,000 acres of avocados being grown there. The
elevation is 1,000 feet at the north end and 3,000 feet at the south end of the avocado
region of Atherton. The north end has granitic soil, with somewhat poor drainage, and
receives less rainfall. The major avocado variety is Shepard, a minor California variety
that does very well in the Atherton area. The Shepard is also the subject in the
successful market development program mentioned above. The south end of the
Tablelands has deep, well drained basalt soil. It also receives a lot more rain, averaging
50 inches per year. Most of the water needs of agriculture are provided by canals from
Tinnaroo Lake on the Barron River. South Atherton also produces Shepard avocado,
but its main variety is Hass. Fuerte, Sharwill, and Rincon are also grown.
Root rot is a problem with several of the avocado groves in the Atherton Tablelands. All
the growers who do not have root rot know they will have root rot and will be injecting
with one of the several available phosphonate products. In the meantime they utilize
heavy mulching (Figure 1). They apply four bales of straw each year on three-year-old
trees, or a twelve inch layer of grass down the tree rows every two years on trees six
years and older—about ten bales of straw. (Dr. John Menge's work at UC-Riverside is
finding that mulch does a lot more than just aerate the soil.)
Just as in California, pruning and grove thinning by tree removal are subjects of debate
and action. Ted Winston, a former Extension Agent and my guide for a day, arranged a
grower field meeting at Vit and Peter Kochi's grove. We talked about root rot, pruning,
marketing, and production comparisons. Later that afternoon and evening Don Lavers
and I observed the Laverses' pruning program on previously 35-foot-tall trees. The
accompanying picture (Figure 2), saves me a thousand words: one cut removed a 13inch diameter, 30- foot-tall branch. Mr. Lavers painted the wound with a copper based
paint, and the now exposed branches with a diluted white latex paint to avoid
sunburning. The remaining branches are still producing. It is believed that little to no
production will be lost; production should increase as new interior branches develop.
Pruning his trees is only one part of retired veterinarian Don Lavers's avocado
operation. Upon returning from the field tour with Ted Winston, I found Don and Del
Lavers in their packing house personally packing the remains of the days harvest, and
arranging their delivery schedule— definitely "hands-on" grove owners. Their grove is
partly encircled by a winding river. They had cleared the land, planted it themselves,
starting in 1981, and lived in a tent until their home was completed. Some special
friends they introduced me to were the rock wallabies who visit them every evening.
Rock wallabies are one-foot tall kangaroos. I am indebted to Don and Del Lavers for a
truly enjoyable, educational, heartwarming visit.
NAMBOUR, MAROOCHY. AND DOCTORS TONY WHILEY AND CLIVE KAISER.
Previous arrangements had been made to meet Tony Whiley at the Department of Plant
Industry's research center in Maroochy. This required a one hour flight south from
Cairns and a one hour drive north to Nambour, Dr. Whiley's hometown. The flight south
was all along the coastline and included an awesome panorama of the Great Barrier
Reef. The drive from Brisbane up to Nambour covered the kind of country California's
San Gabriel and Pomona valleys must have resembled in the early 1900s: excellent
climate, no smog, abundance of plant and animal life, and an absence of housing tracts.
Australia still has fewer than 30 million people.
The next morning I was to drive out to the research center, but was pleasantly
surprised. A group of South African avocado growers and Dr. Nigel Wolstenholme and
Dr. Clive Kaiser met me at the motel and took me to the center to meet with Tony
Whiley. I had met most of the Voortrekers at their research conference the previous
year. The South African and Australian avocado industries have a great interchange of
cultural and technical knowledge; and this group, too, had stopped off to visit with Dr.
Whiley before going on to the conference in New Zealand.
Dr. Kaiser is currently working under Dr. Whiley via a grant from the Department of
Plant Industries. He is pursuing some of his own projects, mostly pruning techniques,
while being Whiley's right hand on other projects, such as root rot. Most of the groves in
Australia have root rot. Growers continue the quest for a resistant rootstock just as we
in California do. In the meantime, they want to know more about the longevity and
possible weaknesses of phosphonate usage.
On our visit into the Bundenberg area of central Queensland, Dr. Kaiser showed his
pruning project and John Dorian, a mango and avocado grower, explained his
hedgerow-pyramid pruning program on mature Hass trees. Dorian uses mechanical
hedging machines on one side of his tree rows one year and the other side the next
year, while topping all trees two times a year. This definitely maintains his tree size. Mr.
Dorian is also maintaining his production. I keep trying to figure out how to use those
hedging machines on our hillsides in California.
Clive Kaiser's pruning technique is very different. His work is both on young and newly
staghorned trees. His objective is to keep the trees shorter than 12 feet tall, with a dome
shape, and create early fruiting. This is especially difficult on the staghorned trees which
grow back so vigorously and have an excess of new branches. Normally, these trees
grow the next two years; and by the time the first fruit is harvested, the trees are already
fifteen feet tall. Kaiser's technique on trees he plans to staghorn is to girdle at bloom
time the branches he plans to cut. He girdles the branches at the height he plans to cut
them. With the girdled branches fruiting heavier than normal, the regrowth after they are
cut should be less vigorous. As the new branches grow, they are nipped at their tips.
This temporarily stops growth. The next step of unique significance is that he then
prunes the new branches back to where the last growth flush began. This zone where
growth stopped and then began again is commonly called a "knuckle." The knuckle has
several buds on it. When pruned at the knuckle, several of the buds commence growth
of new branchlets. These branchlets are not vigorous, and Kaiser pointed to several of
them that were less than 12 inches long and were beginning to flower (September is
early spring in Australia). The staghorned trees pruned by Clive were compact, only 4-5
feet high one year after pruning, and were going to bloom.
Dr. Kaiser's procedure on young trees is much easier in that it starts with nipping the
branch tips and later pruning back to the knuckles. We saw squat, compact, healthy
one-year-old trees that were going to bloom.
ROOT ROT AND PHOSPHONATES
As mentioned, Drs. Whiley and Kaiser are researching Phytophthora cinnamomi (P.c.).
They are doing some very interesting work. The most interesting is their study of
phosphonates. One of the projects is studying whether or not phosphite (free ion form of
phosphonate) exudes from the roots of avocados; if so, how much, how fast? Their
work is being done "airponically"—their test trees are grown in big wood boxes with no
support from soil and or water. The root systems are mist sprayed at frequent enough
rates to keep the trees growing. The water that drips off the roots is collected and
analyzed for phosphite. Their first conclusion is confirmation that avocado roots do
exude phosphites that have been applied through the leaves. The work continues.
Work on possible tolerance of P.c. to phosphonates is ongoing. Preliminary results were
later to be reported by Dr. Kaiser in a presentation at the conference in New Zealand.
There are indications that tolerance may be developing in some situations. This is one
trial where negative results are hoped for.
As in California, Australia hopes to find a rootstock tolerant to P.c. Australian trials with
our most promising rootstocks are not showing success. Their own Velvik rootstock, as
seedling or clonal, performs better. Dr. Menge of UC-Riverside is testing Velvik and
Evstro, both given to him by Australian researchers. Velvik has been difficult to grow
under California conditions.
This visit to Australia was short, but dynamic. I am appreciative of the courtesy,
openness, and friendship shown me. The growers and researchers all shared their
knowledge, experiences, and results while driving me around, hosting meetings and
receptions, even providing or arranging places to sleep. Before we left, Tony Whiley
gave all of us a software disk of his Avoinfo program bibliography—another benefit of
our international liaison.
Good-bye to a continent; hello to an island . . .
NEW ZEALAND
The conference was officially to begin September 21 in The Millennium Hotel in
Rotarua, on the north island of New Zealand, but a pre-conference tour of the avocado
industry in the Northlands was conducted September 18-20. About 150 people were
placed on three buses and driven north from Auckland through the beautiful, 200 mileslong Northlands peninsula.
Of New Zealand's 2,000+ acres of avocados, 1,000 acres are in the Northland
peninsula. During the three day tour we visited at least ten avocado groves and one of
their major packing houses. Their main variety is Hass, with Fuerte, Reed, and Zutano
used primarily as pollinators for the Hass. Hass, Zutano, and Reed are also used as
rootstocks. One grower found Reed to be the most vigorous and best producer of the
rootstocks. Total production for the Northland this year will be 2,700,000 Ibs.; they
forecast 10,000,000 Ibs. by the year 2008. New Zealand's total production currently is
5,000,000 Ibs., with 17,000,000 projected by 2008. At least half of New Zealand's fruit is
exported to Australia, but more and more is being sent to "California." Greater exports
to the U.S. are definitely projected. After seeing several trees with over 1,500 pounds
per tree, I am convinced of their production capabilities. Similar to California, however,
they too can have severe alternate bearing. Their main problem is low temperatures
during bloom, hence poor fruit set.
Pruning was a major topic during the tour, and later during conversations at the
conference. Most of the groves in New Zealand are planted on fairly wide spacing such
as 30X30 ft. or 35X35 ft. As trees become crowded, every other row is removed (yes,
30X60 ft.). They are doing more pruning in hope of avoiding whole row removal. While
no definite programs were advised, we did see some very impressive machinery for
performing the pruning: escalating platforms as high as 45 feet from which hydraulic
pruners and saws can be used, a massive chipper that can mulch avocado and
eucalyptus logs 15 inches in diameter, and helicopter spraying between windbreaks
spaced only 300 feet apart.
Imagine trees 35 feet tall, 25 feet wide, sides full of fruit all the way down to the ground.
THE CONFERENCE: "SEARCHING FOR QUALITY"
The thrust of this joint conference of the Australian and New Zealand avocado
associations was growing, packing, storing, shipping, and selling high quality fruit. Dr.
Jonathan Cutting was the program organizer. Dr. Cutting made sure all the aspects
were covered. Speakers from other countries included Alva Snider, past chairman of
our California Avocado Commission. His presentation stressed the value of growers
having a central organization working for the growers benefit establishing directions on
consequent programs, use of promotion themes such as the "Magic of California", and
adapting to changing markets. He also emphasized grower-problem programs such as
the "Water Task Force" that so far has saved us over $30 million in water costs.
The Republic of South Africa's Bill Blanden shared that country's marketing program to
develop the United Kingdom as its primary export market which started with a doctorate
thesis, "The Avocado Market in European Countries". The study for the thesis was
partially funded by the Republic of South Africa's avocado growers' organization,
SAAGA. There were nine conclusions; the three most relative to California are:
• Lack of knowledge of avocados is a major obstacle for furthering increased
sales,
•
Consumers emphasized quality above price (we knew this),
• There is a very real need for promotion to stimulate demand ahead of supply;
otherwise prices fall to levels that make it uneconomic to bring them back up.
A LESSON LEARNED FOR MINOR VARIETIES
A very revealing speech was given by Rob Robson on developing a marketing program
for a minor greenskin variety, the Shepard, for the northern Australian avocado growers.
This was a program I learned a lot about during the Australia segment of this trip. The
grower/government program took a lesser-known, high quality fruit from a limited market
to a full-blown successful promotion. They fully integrated the grower, harvester,
transporter, packer, merchandiser, retailer, and the consumer. It was their survey of the
of the consumers that revealed housewives in Australia expect to find one bad avocado
out of every four they buy. Part of their successful promotion program used pictures of a
halved Shepard avocado with nice yellow color and the statement "Nature's Own
Butter". They cross-merchandised with a salad dressing (Kraft), a fresh cut salad
manufacturer, and a potato chip company. All of this for the only 12— to 14—weeks
season of the Shepard.
The "butter" statement was backed up by an anecdote by another speaker, Russell
Harray, who related that the population is aging. His mother eats avocados every day.
Why ? Because she's been told not to eat butter or margarine. She uses avocado as a
spread instead.
INSTEAD OF HAND SQUEEZING—SMALL MACHINE MEASURES AVOCADO READINESS To EAT
The development and use of the "Anderson firmometer" was described by Anne White
of the Horticulture and Food Research Institute of New Zealand. The firmometer gives a
numerical measure to fruit softness instead of what even industry experts resort to:
hand squeezing of the fruit. Most consumers are not adept with the hand-squeeze. The
original firmometer was developed by South African researchers. It measures
displacement of the button of the fruit when pressure is applied. The Anderson
firmometer has a digital meter and a few other modifications for simplicity and accuracy
that allow anyone to measure fruit life and softness—even consumers. [How about
having each store place a firmometer at its avocado display?]
PRUNING
This topic was covered only by an apple researcher. I arranged one informal meeting of
growers and researchers working on this subject. The most important question
answered for me was, "What is the best program for a grower with a completely
crowded grove and trees over 35 feet tall?" Many California growers have this problem.
Many possibilities were discussed with the consensus being, "stump or staghorn the
trees back to 5-12 feet tall, one section of the grove at a time. A section would probably
be one-fifth or one-fourth of the grove." Take this recommendation and start cutting.
Increased production and easier management are the rewards.
A DWARFING ROOTSTOCK
Dr. John Palmer, the apple researcher referred to earlier, was very enlightening as to
the production and pruning techniques of the apple industries of the world. When asked
what advice he had for the avocado industries he said, "You have to develop a dwarfing
rootstock." Growing 45 foot—tall trees didn't impress him.
A side trip after the conference was to visit an avocado grower on the east side of the
North Island of New Zealand, David Grey—a college classmate and good friend. David
is testing a dwarf rootstock that shows decreased growth of six-year-old Hass, Gwen,
and Esther trees. The trees are grown on a Zutano root stock with Colin V33 dwarf
stock grafted onto the Zutanos; then with Hass, Gwen, or Esther scions grafted onto the
Colin V33 interstock. The six-year-old trees are 7-9 feet tall, about two—thirds the size
of comparable 6-year-old trees. They had a good crop. The Colin V33 is known to have
a virus complex, which is probably causing the dwarfing. UC-Riverside has the Colin
V33, and Dr. Dodds of UCR has the ability to screen the viruses and check for
transmissibility (a possible problem).